New Blood Test Improves Screening for Prostate Cancer

A new test is better at detecting aggressive prostate cancer than measuring prostate-specific antigen (PSA) levels. The new test discovers aggressive cancer earlier and reduces the number of false positive tests and unnecessary biopsies. The results were published in The Lancet Oncology (doi:10.1016/S1470-2045(15)00361-7).

Prostate cancer is the second most common cancer among men worldwide, with more than 1.2 million diagnoses in 2012. As the number of men with prostate cancer diagnoses increases, the number of diagnoses per year is estimated to be more than 2 million within 20 years. PSA tests are used to diagnose the disease, but use of the procedure is controversial.

"Today, men who don't have cancer or who have a form of cancer that doesn't need treating must go through an unnecessary, painful, and sometimes dangerous course of treatment. On top of this, PSA misses many aggressive cancers. We therefore decided to develop a more precise test that could potentially replace PSA."

The STHLM3 test is a blood test that analyzes a combination of 6 protein markers, more than 200 genetic markers, and clinical data (age, family history, and previous prostate biopsies). The test has been developed by researchers at Karolinska Institutet in collaboration with Thermo Fisher Scientific, which provided the protein and genetic marker assays used in the clinical study.

The study included 58 818 men from Stockholm age 50 to 69 years was conducted between 2012 and 2014. All participants underwent the STHLM3 test and PSA and results were compared.

The results show that the STHLM3 test reduced the number of biopsies by 30% without compromising patient safety. In addition, the STHLM3 test found aggressive cancers in men with low PSA values (1-3 ng/mL), which are cancers currently going undetected.

"This is indeed promising results. If we can introduce a more accurate way of testing for prostate cancer, we'll spare patients unnecessary suffering and save resources for society," said Grönberg. "The STHLM3 tests will be available in Sweden in March 2016, and we will now start validating it in other countries and ethnic groups."

The Stockholm County Council financed the study. Professor Grönberg is a researcher at the Department of Medical Epidemiology and Biostatistics at Karolinska Institutet.